The Study Of The Viscoelasticity Of Polymer Matrix Composite And Its Application

With the development of science and technology, the proportion of composite materials in all industries is becoming bigger and bigger. At this point, the service life of composite material has drawn attention. The researches of the viscoelasticity properties of composites have begun in both home and abroad. The current research mainly focused on composite material macroscopic phenomenological theory analysis and experiment. By contrast, few research was carried on the mechanism of the viscoelasticity of the composite materials from microscopic. Based on this point this paper has performed related research.This paper tried to start from the viscoelastic model of the matrix materials and proposed a viscoelastic model of unidirectional fiber-reinforced composite plates. Using the Laplace transformation and inverse Laplace transformation to change the equilibrium equation we deduce the expression of the viscoelastic constitution relation which was similar to the expression of matrix materials.According to the verification of experiment about the matrix materials and unidirectional fiber-reinforced composite plates, this model could express the creep of the unidirectional fiber-reinforced composite plates accurately. And on the other hand, this paper suggested a new method to get the viscoelasticity of composite materials directly from the viscoelasticity of matrix materials. The method established the foundation of the discovery of the laminate viscoelasticity.Based on the classical laminated composite material theory this paper has also deduced the viscoelastic parameters of composite laminated plate matrix expression, and moreover, we built a model to deduce the viscoelastic properties of composite material from the viscoelasticity of polymer matrix. Finally, based on the derivation process involved many Laplace transform and its inverse transformation, this paper realized the numerical calculation of the formula by MATLAB.During the research, we carried a set of composite laminated plate creep experiment. Based on the comparison between the material creep compliance and the theoretical calculation results, although there were some inevitable errors it could be still proved that the theoretical calculation results can reflect the change trend of composite creep compliance. In additional, we pointed out the items need to pay special attention to in the experiment.Combined the composite material mesoscopic mechanics theory with polymer material viscoelasticity theory, this paper has deduced the way to find out the viscoelastic properties of composite laminated plate from the viscoelasticity of matrix material and elasticity of reinforcing material. We have verified the correctness of the theoretical formulas by the creep experiments of matrix material, unidirectional laminates and laminated composite plate. This method may provide an optional way to change the current situations of long-term performance experiments about the composite materials which cost long time and large count of money.